Informatics, Robotics, Microelectronics

Laboratory of Montpellier, France

Mixed Research Institute:

- CNRS (French National Centre

of Scientific Research)

- Montpellier 2 University

On PKM with articulated

travelign plate abd large

tilting angles

Sébastien Krut

François Pierrot

Olivier Company

LIRMM

Speaker

(2)

Goals of this paper

Propose a new kinematics with:

3 translations

2 rotations

With large tilting angles

(ie with more than +/- 45 degrees for both)

For example for 5 axis milling

(3)

Presentation summary

Points adressed:

General solutions to reach large tilting angles

Solution for 5-axis (3T-2R) Eureka

Modeling & Workspace

Conclusion

(4)

Remote actuation

Constraint:

Actuators as close as possible to the base

Problem well known for one rotation.

Solutions :

Remote actuation

Hybrid architecture

Redundancy

« Natural » solutions

Articulated traveling plate

(5)

Remote actuation

Revolute joint is added

on the traveling plate

and « tele-operated

from the base

Bad sevice life of elements

ABB flexpicker

(6)

Hybrid architecture

High moving masses (Actuators far from the base)

DS – SprintZ3Two mechanisms

assembled in a serial

way

Each one can be

optimized

(7)

Hybrid architecture

Two mechanisms

assembled in a serial

way

Each one can be

optimized

High moving masses (Actuators far from the base)

Tricept

(8)

Hybrid architecture

Left hand / right hand

Shared dofs

Not realistic for manipulation

(9)

Redundancy

Several types of redundancy exist:

Actuation redundancy

Kinematic redundancy

(10)

Actuation Redundancy

Needs force control

Archi prototype

Generates

internal forces

(11)

Actuation Redundancy

(12)

Kinematic Redundancy

Speed-R-ManComplexity increases

(13)

“Natural” solutions

Limited scope

Nevertheless some

« natural » solutions

existDual 4

(14)

“Natural” solutions

(15)

Articulated traveling plate

Traveling plate is splitted in

several parts

Supports motion

transformation /amplification

Hita STT

Complexity increases

(16)

Articulated traveling plate

Gears (Ratio 4 :1)

H4 prototype

Par4 prototype

(17)

Articulated traveling plate: Par4

(18)

Articulated traveling plate

I4R prototype I4L prototype

(19)

Articulated traveling plate

(20)

Articulated traveling plate

Twice mechanism

(21)

Back to our problem….

3T – 2R with large tilting angles

Combine solutions presented before :

Articulated traveling plate

Redundant actuation

Find a new mechanism :

(22)

Kinematics of Eureka

(23)

Kinematics of Eureka

or

(24)

Kinematics of Eureka

Practical

design

(25)

Kinematics of Eureka

Practical

design

(26)

Kinematics of Eureka

(27)

Modeling - workspace

Jx

_x = Jq

_q

Analytic direct and

forward kinematic models

for postion relationship

Diagonal matrix

Classical linear models

for velocity relationship

·nT (s £ n)T v vT n

nT (s £ n)T v 0

¸

(28)

Modeling - workspace

O

(m )z

(m )y

(m )x

1O

4O

2O

3O5

O

6O

Workspace shape forcond(J ¡ 1

qJ

xW ¡ 1

x) < 8

(29)

Conclusion

Presentation of several solutions to achieve

large rotations with PM

Presentation of a new kinematics with:

2 rotational dof and

large workspace

Emphasis on the next prototype ….

(30)

Conclusion

Spherical

Revolute

Haptic interface

(31)

Thanks !!!to you and to my team…

Contact: company@lirmm.fr

Vincent Nabat

François PierrotSébastien Krut

Olivier Company Vincent Bégoc

Walid Zarrad Mickaël SauvéeEtienne Dombre

Philippe Poignet

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